Trash bags are typically formed from two panels of thermoplastic materials that are sealed along opposing vertical sides. The horizontal seam along the bottom of the panels is also sealed. The top side of the panels, however, is not sealed and provides an opening or mouth for access to the interior of the bag. The trash bag is inserted as an interior liner of a formed container or receptacle. The bag mouth is then loosely laid over the top end of the receptacle to provide an unobstructed opening for inserting trash into the bag.
A differentiating feature in many trash bag designs, however, is the bag closure system. In the typical trash bag closure system, the bag adjacent to the opening is gathered together at a point some distance below the mouth. If there is sufficient bag length above the gathering point, this length may be tied into a knot to secure its contents. Otherwise, a separate bag tie may be used to secure the bag from reopening. Typical bag ties are paper coated flexible wires or a plastic strip with a self-adjusting locking mechanism. Having separate tie mechanisms is often undesirable due to the additional expense in manufacturing and the inconvenience they cause the consumer.
One way to avoid these problems is to have a closure system integral to the overall bag design. One particular integral bag closure system includes tie members that are simple extensions of the bag body. In this system, an extra length of plastic integral to the bag body extends above the mouth on opposing sides of the bag. Now instead of gathering the plastic at a point below the mouth, the mouth may in essence become the gathering point and the two lengths of plastic extending upwardly from the mouth are used to tie a knot in order to secure the bag contents.
Another integral bag closure system includes a drawtape or drawstring internal to a hem formed along the mouth of the bag to form a so-called cinch. The hem may be formed by folding the plastic of the bag body over itself a short length and heat sealing the seam with the drawtape/drawstring internal to the hem. In this design, the hem is provided with one or more access holes that allow the drawtape/drawstring to be pulled through, gathering the bag along its mouth to secure its contents. The drawtape/drawstring advantageously serves as a handle for which to carry the bag. Furthermore, if two access holes are provided, the drawtape can then be tied together in a knot to ensure that the contents stay inside the bag while also providing a handle for which to carry the bag.
One shortcoming of traditional trash bags as well as trash bags with integral closure systems is the securing of the bag mouth to the opening of the receptacle. For many trash bags, the bag mouth is loosely laid over the container edge. When consumers fill the trash bag, the bag mouth often becomes detached from the formed container and consequently falls down inside the container. This may occur from the shear weight of the inserted trash or from simply dragging the mouth into the bag as the consumer repeatedly inserts trash into the bag. The consumer must then pick up the bag relative to the container and put the mouth back over the top edge of the container. Otherwise, the consumer risks missing the inside of the bag completely and having trash in immediate contact with the inside surface of the container. This defeats the purpose of the bag and creates a nuisance for the consume.
A mouth securing system has been proposed to overcome this shortcoming by inserting an elastic ring inside a hem formed along the mouth of the bag. The ring or loop element is not attached to the bag but instead just freely floats within the formed hem. The ring may be completely made from elastic material or have only a portion made from elastic material. This mouth securing system may be used with a cinch-type closure system. A number of disadvantages exist in this design. First, because the elastic ring is not attached to the bag, it requires that a hem be formed along the mouth of the bag which adds to the manufacturing cost of the bag. Without the hem, the ring would simply slide off the bag in its unstretched state. Second, this design requires that the loop completely traverse the mouth of the bag. Again, because the elastic ring is free floating and not attached to the bag, stretching along the mouth can only occur if the ring forms a closed loop. Anything less than a closed looped ring would not be effective in this design.
Another mouth securing system has been proposed that augments a closure system utilizing a drawtape design with an elastic member adhered to the drawtape. In essence, the securing system is incorporated into the closure system. In this design, a section of the drawtape is gathered into folds forming a plurality of crests and troughs. An unstretched elastomeric strip is then attached to the troughs of the gathered drawtape. This provides the drawtape with a level of elasticity related to the length of drawtape attached to the elastic strip. When the drawtape is stretched, the elastic strip stretches moving the drawtape crests closer to the troughs. The drawtape may stretch until the crests and troughs are substantially coplanar. Any further stretching results in plastic deformation of the drawtape just as if there were no elastic member. The augmented drawtape is incorporated within a hem about the mouth of the bag as previously discussed. For this design to be effective as a way to secure the bag mouth to the receptacle, the unstretched mouth opening must be smaller than the receptacle opening. In this way, the mouth must then be stretched to cover the container opening, thus creating an elastic restoring force that secures the bag to the receptacle.
This design, however, also has some disadvantages. First, this mouth securing system is limited to trash bag designs having closure systems that employ drawtapes or drawstrings. This is a significant disadvantage because the drawtape manufacturing process is more expensive, requires additional materials, and requires more steps than other closure systems. Furthermore, this design attaches the elastic member to the drawtape at discrete locations along the drawtape, i.e., at the troughs of the gather sections, which complicates the manufacturing process and thereby may add cost to the bag.
Therefore, a need exists for a system that secures the mouth of a trash bag to a container but that overcomes the disadvantages of the previous designs and additionally works with a host of closure systems.